The OPENAIR Circus is an amazing phenomenon with an improbable history. If you’ve got kids, take them this weekend and think about joining. After this weekend, the next major performance will be in Boston’s First Night parade.

The remaining performances this summer are today at 2 and 7 and Sunday at 2, at Nunziato Field near Union Square at the corner of Vinal Ave. and Summer Street (where the Southern Junior High used to be).

There are about 150 kids in the circus. Classes in circus and circus-like skills–stilting, juggling, mime, unicycling, and many others–run for five weeks, once a week, and many kids take more than one class. Families pay $20 per child or $30 for the family, and that covers any number of classes.

During the last two weeks, each class works out an act, which they perform on the final, crescendo weekend.

Some teachers are paid, but essentially, the circus is a volunteer community.

This is the circus’ 23rd year. It started because of a remarkable artist, Be Allen, who bought a burned out foundry next to the railroad tracks. She lived in part of it, and decided to hold community events in the rest, which was open to the air because the fire had destroyed the roof.

For several years, she held summer performances there, on a stage built by volunteers. I remember a Kafka play, a battle of the bands (you can imagine how much the neighbors loved that), and a summer devoted to “local heros” — Vietnam veterans and their stories.

One year, members of the Ninots performing troupe put on a circus-like show, and Jane Urban stayed to teach some kids stilt-walking, which is a perfect skill: looks impressive, actually very easy.

Be and friends decided the following summer’s theme would be the circus, and it went so well they just kept doing it–a group of about 10 people organizing, building, sewing, squabbling, teaching, creating a community.

Later, OPENAIR, led by an enormous contingent of stilt-walkers of all ages, started marching in the First Night parade.

When Be retired to Arizona and sold her place, I was sure the circus had run its course. It was totally dependent on a free performance space, I thought. But the board discovered they could rent a tent and a stage for only a few thousand dollars,   which they raise with fees and donations, and it’s better than ever at Nunziato.